It is well-known that the abdominal and glutaeus muscles are difficult to isolate and strengthen. Many hours and years of exercise is generally necessary to produce significant effect on the abdominal musculature. The prior art discloses three categories of muscular development methods and apparatuses as follows:
full range of motion; PA1 limited range of motion; and PA1 compression devices.
The full range of motion devices are typified in U.S. Pat. Nos. 4,290,597; 3,558,130; and 4,616,825. Each of these devices relates to a modification of the well-known sit-up exercises. Such inventions suffer from two major drawbacks. First, many muscle groups are indiscriminately exercised in addition to exercising of the target abdominal muscles. This results in slow development of the musculature. Second, the flexion of lumbar and thoracic spine over a significant range of motion may exacerbate previous low back and other injuries.
Limited range of motion inventions are typified by Schleffendorf, U.S. Pat. No. 4,290,597, generally involving an exercise called an "abdominal crunch." While such inventions may isolate the abdominal musculature, the positioning of the operator is such that maximal benefit to the operator is not achieved. The glutaeus maximus and glutaeus medius are even more difficult to isolate and exercise than the rectus abdominis and obliquus abdominis externus. There is no prior art apparatus known to the applicant dedicated to that purpose.